<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>


</head>
<body>

<div class="login-box">

    <div>用户名: <input type="text" id="username"></div>
    <div>密码: <input type="password" id="password"></div>
    <div id="err" >
        <div>dd</div>用户名或者密码错误</div>
    <div>
        <button id="btnLogin">登录</button>
    </div>

</div>

</body>
<script src="mock/user.js"></script>
<script src="js/9.login.js">

    function jisuan(num1,num2,callback){
         return callback(num1,num2);
    }

    jisuan(1,2,function (num1,num2){

    })

</script>
</html>